Conventionally, as a substrate processing system for performing various plasma processing, such as an ion doping process, a film forming process and an etching process, on a substrate, there has been known a cluster type substrate processing system wherein plural processing apparatuses are disposed radially around a common substrate transfer chamber.
Such a cluster type substrate processing system, as shown in FIG. 15A, includes, e.g., two substrate processing apparatuses 151 for processing a substrate; a loader module 152 for transferring the substrate from a substrate cassette (not shown); two substrate loading/unloading chambers 153 for performing loading/unloading of the substrate into/from the loader module 152; and a substrate transfer chamber 154 as the substrate transfer apparatus disposed between the substrate processing apparatus 151 and the substrate loading/unloading chamber 153. (see, e.g., U.S. Pat. No. 5,855,681)
The substrate transfer chamber 154, as shown in FIG. 15B, has a gas introduction unit 155 for introducing a gas thereinto and a pumping unit 156 for exhausting the inside thereof to vacuum. Further, in the substrate transfer chamber 154, there is provided a handling device 157 as a substrate transfer mechanism for transferring the substrate, and a gate valve 158 that can be freely opened and closed is installed at a side wall thereof contacting with the substrate processing apparatus 151 or the substrate loading/unloading chamber 153. The handling device 157 is a scalar arm type handling device having a plurality of arm members and a rotation table, and transfers the substrate into the substrate processing apparatus 151 or the substrate loading/unloading chamber 153 via the gate valve 158.
However, in case the substrate is continuously processed by using the aforementioned cluster type substrate processing system, when the handling unit 157 transfers the substrate, particles transferred into the substrate transfer chamber 154 by the handling unit 157 together with the substrate and/or particles, cut powder, produced upon the operation of the handling unit 157 are attached to the substrate. As a result, for example, in an etching process, the attached particles serve as a mask to cause an etching deficiency. Further, in a film forming process, the attached particles serve as a core to grow, resulting in deterioration in quality of film.